You can lose on both, but you can wipe out everything in one night on gambling, compared to MLM if it's legit you have products or services to sell, I have been into 5 MLM in the past and I made profits from my referrals and sales, you can only lose here if you are not active in recruiting and selling the product or services, your chances to lose in MLM is lesser than if you are gambling, in MLM you have to employ strategy on gambling there is no strategy only luck is involved.